Metamath Proof Explorer


Theorem s7cld

Description: A length 7 string is a word. (Contributed by Mario Carneiro, 27-Feb-2016)

Ref Expression
Hypotheses s2cld.1 ( 𝜑𝐴𝑋 )
s2cld.2 ( 𝜑𝐵𝑋 )
s3cld.3 ( 𝜑𝐶𝑋 )
s4cld.4 ( 𝜑𝐷𝑋 )
s5cld.5 ( 𝜑𝐸𝑋 )
s6cld.6 ( 𝜑𝐹𝑋 )
s7cld.7 ( 𝜑𝐺𝑋 )
Assertion s7cld ( 𝜑 → ⟨“ 𝐴 𝐵 𝐶 𝐷 𝐸 𝐹 𝐺 ”⟩ ∈ Word 𝑋 )

Proof

Step Hyp Ref Expression
1 s2cld.1 ( 𝜑𝐴𝑋 )
2 s2cld.2 ( 𝜑𝐵𝑋 )
3 s3cld.3 ( 𝜑𝐶𝑋 )
4 s4cld.4 ( 𝜑𝐷𝑋 )
5 s5cld.5 ( 𝜑𝐸𝑋 )
6 s6cld.6 ( 𝜑𝐹𝑋 )
7 s7cld.7 ( 𝜑𝐺𝑋 )
8 df-s7 ⟨“ 𝐴 𝐵 𝐶 𝐷 𝐸 𝐹 𝐺 ”⟩ = ( ⟨“ 𝐴 𝐵 𝐶 𝐷 𝐸 𝐹 ”⟩ ++ ⟨“ 𝐺 ”⟩ )
9 1 2 3 4 5 6 s6cld ( 𝜑 → ⟨“ 𝐴 𝐵 𝐶 𝐷 𝐸 𝐹 ”⟩ ∈ Word 𝑋 )
10 8 9 7 cats1cld ( 𝜑 → ⟨“ 𝐴 𝐵 𝐶 𝐷 𝐸 𝐹 𝐺 ”⟩ ∈ Word 𝑋 )